This paper introduces asymmetric awareness into the classical principal-agent model and discusses the optimal contract between a fully aware principal and an unaware agent. The principal enlarges the agent's awareness strategically when proposing the contract. He faces a trade off between participation and incentives. Leaving the agent unaware allows him to exploit the agent's incomplete understanding of the world. Making the agent aware enables the principal to use the revealed contingencies as signals about the agent's action choice. The optimal contract reveals contingencies that have low probability but are highly informative about the agent's effort.

A buyer makes an offer to a privately informed seller for a good of uncertain quality. Quality determines both the seller's valuation and the buyer's valuation, and the buyer evaluates each contract according to its worst-case performance over a set of probability distributions. This paper demonstrates that the contract that maximizes the minimum payoff over all possible probability distributions of quality is a screening menu that separates all types, whereas the optimal contract for any given probability distribution is a posted price, which induces bunching. Using the ε-contamination model, according to which the buyer's utility is a weighted average of his single prior expected utility and the worst-case scenario, the analysis further shows that for intermediate degrees of confidence, the optimal mechanism combines features of both of these contracts. the participants of various seminars for very helpful comments.

We study directed search equilibria in a decentralized market with adverse selection, where uninformed buyers post general trading mechanisms and informed sellers select one of them. We show that this has differing and significant implications with respect to the traditional approach, based on bilateral contracting between the parties. In equilibrium, all buyers post the same mechanism and low‐quality sellers receive priority in any meeting with a buyer. Also, buyers make strictly higher profits with low‐ than with high‐type sellers. When adverse selection is severe, the equilibrium features rationing and is constrained inefficient. Compared to the equilibrium with bilateral contracting, the equilibrium with general mechanisms yields a higher surplus for most, but not all, parameter specifications.